Tag Archive for: cardiovascular health

How Many Steps Do We Need?

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Last week, we talked about how to lower blood pressure using a form of weight training called isometrics. As I made clear, you won’t look like a body builder, but it can help your cardiovascular health. This week, we’ll look at two recent studies to clarify how much aerobic exercise we need to reduce the risk of all-cause and cardiovascular disease mortality.

The typical recommendation for aerobic exercise is 10,000 steps per day. That was based more on marketing than on science, but it has stood as the standard for years—until recently. Several studies have shown the actual amount may be between 4,000 and 7,000 steps per day.

In a recently published study, researchers included data from 17 studies and over 225,000 subjects. They tracked the subjects for just over seven years to find out all-cause mortality and cardiovascular disease mortality. One more thing: all the data were collected electronically as opposed to relying on some sort of mechanical device that underestimates or overestimates steps per day.

After using meta-analysis, the researchers used 3,900 steps per day as a baseline for the median risk of mortality. For every 500 additional steps per day, the mortality risk decreased 7% and for every thousand additional steps per day it decreased 15%. As the number of steps increased, the cardiovascular and all-cause mortality risk decreased until about 12,000 steps where it leveled off.

Going with our theme of doing just enough to reduce our mortality rate, it would seem that 4,000 steps per day, whether as part of your regular day or in addition to your everyday activity, gives a baseline of protection. But do you really have to invest that much time? We’ll check that out on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: Eur J Prev Card (2023) 00, 1–11 https://doi.org/10.1093/eurjpc/zwad2292

Health Habits: Just Do Better

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Let’s finish up our look at the recent paper that concluded we’re doing poorly when it comes to our health habits (1). If you thought smoking and exercise were underwhelming, today we’ll look at diet and body fat.

When it comes to following the U.S. Department of Agriculture Dietary Guidelines, just under 38% hit that goal. I’ve talked about this a lot over the years, and this isn’t a debate over what constitutes a good diet. While we are doing somewhat better, adults do not eat enough vegetables, fruits, or beans, and we still . . .

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Why Optimism Isn’t Enough

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In the messages this week, we’ve looked at a study that examined an optimistic mental state along with health metrics related to cardiovascular health. I left you with a question on Thursday:

Do you simply need to maintain a positive mental attitude to have great heart health?

I told you I think there’s more to it. Let’s begin by talking about something called The Stockdale Paradox.
The Stockdale Paradox
You might remember Vice-Admiral Jim Stockdale as a third-party candidate for Vice President in 1992. Before that, he was a Navy pilot who was shot down . . .

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Forks Over Knives

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I like writing the Saturday messages because it allows me to review scientific articles or controversies in health in a little more depth. Today I’m going to give you my thoughts on the movie Forks Over Knives, written and directed by Lee Fulker. The movie was exactly what I thought it would be, and at the same time completely different from what I expected. Let me give you a summary of the movie, what I thought was good, and what I found lacking.

Summary

Forks Over Knives chronicles the careers of two scientists, T. Colin Campbell and Campbell Esselstyn, and how they arrived at the same conclusion: plant-based diets will eliminate or dramatically reduce the degenerative diseases we face today such as heart disease, diabetes, and cancer. There are a couple of other well-known plant-based diet activists including Dr. John McDougall and Dr. Neal Barnard from the Physicians Committee for Responsible Medicine (PCRM).

The movie also tracked several people, including the writer, who changed to a plant-based diet and experienced a reduction or elimination of medications, weight loss, and dramatic improvements in measures of health such as blood pressure and blood cholesterol.

As you watch the movie, you’re drawn into the purported benefits of the plant-based diet—everyone would want the results the people in the movie got. The science presented seemed to be clear, from the rodent studies that Campbell used to determine that protein causes cancer to the ongoing study by Esselstyn tracking the cardiovascular health of people given up for dead by their cardiologists. Switch to a plant-based diet and you can give up all medications, improve your sex life, lose weight, improve your fertility, and live longer. Who could argue with that?

What I Liked

In the opening paragraph, I said that the movie was different from what I thought it would be so let me cover that first. I thought this would be the typical “show the slaughterhouse to gross people out” approach, but they didn’t do that at all. That’s a plus, because we get enough violence in other movies.

I thought they did a good job of explaining endothelial cells and why they’re integral to the health of your cardiovascular system (I’m covering that in an upcoming American Heart Month message, so if you don’t know about them, you will.) Ditto for C-reactive protein, the blood measure of inflammation in the body. They also mentioned, but didn’t explain in detail, the role of nitric oxide in the body. I think that’s central to the concept of why a plant-based diet is essential for health.

What I Found Lacking

Most of the problem I had was with T. Colin Campbell’s research, including rodent studies and what he’s most famous for, the China Study.

In his rodent research, he spent years studying the effects of protein on the development of cancer, according to the movie. Basically, he suggested that when you expose rats to animal protein at 20% of caloric intake, they develop cancer. If you lower it to 5%, they stop growing cancer. In one study, he claims they could turn off the growth of cancer like a light switch by switching from 20% to 5%, and then turn it back on by jumping up to 20% again.

What he didn’t say was important. The rats did not spontaneously develop cancer as suggested; only those exposed to high levels of a nasty carcinogen called aflotoxin developed liver cancer with the high-protein diet. And it wasn’t a common protein; it was casein, one of the two proteins found in milk. To make the leap from a protein no one (or no animal) would ever find in nature to suggesting that all protein causes cancer is a stretch—actually it’s like jumping the Grand Canyon. To make this research meaningful, a follow-up study needs to be done using a variety of protein; if that yields the same results, then it’s time to see if the same process applies to humans. But to not give all the details of that research while making such sweeping claims was inappropriate.

Let’s turn to the China Study, one of the largest studies of its kind. Campbell and a Chinese counterpart headed a study to find out the causes of cancer in China. The simple answer was that as dietary protein levels increased, so did all types of cancer; rural areas had the lowest protein intake and the lowest rates of most cancers, while urban areas had a much higher protein intake and thus more cancers. Seems simple, doesn’t it?

Not so fast. There are at least three very important variables that we know affect cancer rates that they didn’t address in the research or the movie:

  • What was the difference in physical activity levels in the rural versus urban areas? The majority of the people in rural areas were farmers who were physically active all day long. We know activity affects disease, so to leave that out of the equation makes the results suspect.
  • The volume of food was different between the rural and urban areas: those in rural areas chronically under eat. Intermittent famine has benefits even if it’s just one day a month. Total caloric intake could more than explain the difference in cancer rates.
  • The people in rural areas weighed less than their urban counterparts. Excess body fat is a risk factor for several types of cancer, including breast and prostate cancer.

As for Dr. Esselstyn, while he has demonstrated that his approach to a plant-based diet will literally bring people back from heart death, there were other factors that have to be considered: he talked with his patients every two weeks; they had cooking sessions in patients’ homes; they had group meetings on a regular basis; his wife taught them how to cook vegetarian meals.

Here’s my question: how do we know that it wasn’t the additional attention that was important to those patients and made the difference in their health? The relationship between mental state and health may be fuzzy, but it exists; people with untreated depression are sick more. I’m not suggesting the diet wasn’t important, but the personal attention had to account for part of the program’s success. Would you get that level of attention from your doctor? If not, you might not get the same results.

The Bottom Line

There’s a scene in the movie that really captures the essence of what I believe: Campbell implies that the members of some of the committees of the USDA are too closely tied to agri-business, and that influences the recommendations the committee makes. Dr. David Klurfeld heads the Committee on Human Nutrition of the USDA. In response to the accusation that committee members have a conflict of interest, he said that there’s also an inherent conflict of interest by Campbell, Esselstyn, and others who promote a plant-based diet: they have chosen a position and defend it with only the data that supports their position. I couldn’t agree more. The problem with the movie is it provides only one view of a very complex subject while omitting important facts and variables.

Having said that, I think you should rent or buy the movie and watch it, because I think moving to a diet that is 80% to 90% plant based is really important for our health. When combined with reducing the refined foods in our diet and eating quality protein, that’s the nutritional approach that will benefit your heart and cardiovascular system.

What are you prepared to do today?

        Dr. Chet